Heat transfer roll



y 13, 1957 F. N. LOCKHART 3,331,434

HEAT TRANSFER ROLL Filed June 29, 1965 2 Sheets-Sheet 1 FIG. "I-

INVENTOR.

F. N. LOQKHART BY July 18, 1967 F. N. LOCKHART HEAT TRANSFER ROLL FiledJune 1965 2 Sheets-Sheet 2 INVENTOR. F. N. LOCK HART United StatesPatent 3,331,434 HEAT TRANSFER ROLL Frank N. Lockhart, Devon, Pa.,assignor to National Drying Machinery (10., Philadelphia, Pa., acorporation of Pennsylvania Filed June 29, 1965, Ser. No. 468,053Claims. (Cl. 165-89) My invention relates to a machine of the type setforth in Roberts Patent No. 2,488,937.

One object of the invention is to produce an improved machine of thetype set forth which, however, is not limited to the specific usesstated in said patent.

Machines embodying the disclosure of the Roberts patent have been soldin fairly large numbers and have operated successfully. But because itwas necessary to limit the liquid content of the jacket to less thanfull capacity, the thermal control probe, which regulates the operationof the burner (which is not shown in said patent), was bared with everyrevolution and produced fluctuations in the heat in-put whichcorrespondingly affected the temperature of the liquid in the jacket.This fluctuation is serious in any event but is more serious when therolls are turned at low speed.

It is therefore a further object of the invention to produce an improvedmachine wherein the thermal control probe is fully submerged at alltimes and at all speeds.

Also, in the patent aforesaid, the burner was located near one end ofthe roll and internal vanes were relied on to circulate the liquid toachieve such uniformity of tem perature as was possible within thelimitations inherent in that type of apparatus.

It is therefore the object of the invention to produce an improvedmachine of the type set forth in which the burner heat in-put isdistributed more evenly over the entire length of the jacket.

Modern industry requires high speed operation and when the apparatus ofthe patent aforesaid was run at high speed, an unaccounted fordifferential in the temperature of the opposite ends of the roll wasobserved. Various studies and experiments were undertaken without anyresults.

While these investigations were going on, applicant received a complaintthat a machine installed in Tasmania, also showed a similar, butoppositely oriented temperature differential. This prompted furtherinvestigations which showed that the machine in Tasmania was identicalwith machines in the latitudes north of Mexico and that the roll wasrotated in the same direction. Further cogitation suggested that theCoriolis effect (which causes a liquid to move in one direction inside aclockwise rotating roll located south of the equator but causes liquidto move in the opposite direction in a clockwise rotated roll locatednorth of the equator) could be responsible for the equal but oppositelyoriented differential.

It is therefore a still further object of the invention to produce animproved machine of the type set forth which is not subject to theCoriolis effect.

The full nature of the invention will be understood from the followingspecification and the accompanying drawing in which:

FIG. 1 is a sectional view of a roll type heat setting machine embodyingthe invention.

FIG. 2 is. an enlarged sectional view looking in the direction of line2-2 on FIG. 1.

FIG. 3 is an enlarged sectional view looking in the direction of line 33on FIG. 1.

The machine illustrated is, in the main, like that shown in the patentaforesaid in that it comprises an inner cylinder and an outer cylinder12 and end walls 14 and 16 which cooperate to define a space 18 forreceiving a 3,331,434 Patented July 18, 1967 heat transfer agent havinga high boiling point such as dowtherm or other satisfactory availableliquid.

Within inner cylinder 10, and entering through end wall 16 is a lineburner 20 which is supplied with fuel from a suitable source, not shown,but subject to control of thermal probe 22 which, as will be explainedbelow, is constantly submersed in the liquid in space 18 and whichregulates the flow of fuel to the burner. The circuitry 26 of controlprobe 22 is conventional and need not be described. It is sufficient tosay that a fall in the temperature of the liquid in jacket 18 causesprobe 22 to increase the flow of fuel and vice versa.

Entering the combustion chamber and passing through end wall 14 is anexhaust pipe 28 which has ports 30 which lead to discharge pipe 32.

In order to allow for expansion and evaporation, a closed jacket 18 canonly be filled up to the level of the broken line in FIG. 2 and asstated, this limitation is responsible for the difiiculties enumeratedabove.

According to my invention I am able to fill jacket 18 completely andstill provide room for expansion.

This is accomplished by providing a reservoir 34 which communicates withjacket 18 through ports 36 which permit movement of liquid betweenjacket 18 and reservoir 34. It will be understood that reservoir 34 isrigidly secured to, for joint rotation with cylinders 10 and 12 by motorM and suitable gearing which need not be described. It should be notedthat the capacity of reservoir 34 is such that it can contain liquidenough, or slightly more than enough, completely to fill jacket 18.

The operation is as follows:

When the machine is at rest, some of the fluid in jacket 18 will flowinto reservoir 34 and the level of the liquid will be at about thebroken line in FIG. 2. When the roll is rotated, centrifugal forcethrows the liquid in reservoir 34 outwardly through ports 36 and intojacket 18 until the latter, is full. The residual liquid adheres to theinside wall of reservoir 34 and leaves the central portion thereof emptyand ready to receive evaporation, if any, and to relieve the liquidpressure which may result from expansion of the liquid in jacket 18. Bythis arrangement, jacket 18 will be completely filled when the machineis in operation and control probe 22 will at all times be fullysubmerged, thus providing better and constant control of the heatin-put. The fact that the jacket is completely filled counteracts theCoriolis effect and makes for more uniform heat transfer.

If desired, vanes 38, like those shown in the patent aforesaid, may beadded further to improve the circulation of the fluid in jacket 18.

What I claim is:

1. A heat transfer roll including:

means defining a jacket adapted to receive a fluid transfer medium,

a reservoir adapted to receive a fluid medium and communicating withsaid jacket, means securing said reservoir to said roll, and means forjointly rotating said roll and said reservoir whereby centrifugal forcedrives fluid from said reservoir into said jacket during rotationthereof,

said reservoir being so related to said jacket that, in the absence ofcentrifugal force, liquid flows from said jacket into the reservoir.

2. The structure defined in claim 1 in which said reservoir is adjacentone end of the roll.

3. The structure recited in claim 1 in which said reservoir and saidjacket are concentric and in which the diameter of the reservoir is notgreater than the smaller diameter of said jacket.

4. The structure recited in claim 1 in which said reservoir and saidjacket have a common axis of rotation a 3 a; and in which the reservoiris nearer the axis of rotation voir to transfer fluid from saidreservoir to said than the jacket. jacket by centrifugal force.

5. A heat transfer r011 including:

means defining a jacket having a predetermined volu- References Citedmetric capacity and containing fluid less than said 5 UNITED STATESPATENTS capacity whereby a fiuid free gap is formed in said 1 7 0 72/1931 Escole 5 j 7 2,488,937 11/1949 Roberts 26- 1 a heater for saidjacket, 2,797,899 7/ 1957 Funk et a1. 16589 X a reservoir communicatingwith said jacket and con- 10 3,022,047 2/ 1962 Swaney 165-89 t" fld' ttlfii't 11 i i m m an a east Su men fi ROBERT A. OLEARY, Primary Examiner.

and means for jointiy rotating said roll and said reser- STREULE,ASSI'SICIHZ Examine!-

1. A HEAT TRANSFER ROLL INCLUDING: MEANS DEFINING A JACKET ADAPTED TORECEIVE A FLUID TRANSFER MEDIUM, A RESERVOIR ADAPTED TO RECEIVE A FLUIDMEDIUM AND COMMUNICATING WITH SAID JACKET, MEANS SECURING SAID RESERVOIRTO SAID ROLL, AND MEANS FOR JOINTLY ROTATING SAID ROLL AND SAIDRESERVOIR WHEREBY CENTRIFUGAL FORCE DRIVES FLUID FROM SAID RESERVOIRINTO SAID JACKET DURING ROTATION THEREOF, SAID RESERVOIR BEING SORELATED TO SAID JACKET THAT, IN THE ABSENCE OF CENTRIFUGAL FORCE, LIQUIDFLOWS FROM SAID JACKET INTO THE RESERVOIR.